Présentation Restoration of arid ecosystems in the western United States (US) is often constrained by low and variable moisture and invasion by exotic species. After disturbance, variability in resources as well as inherent soil moisture and temperature regimes may influence the susceptibility of an ecosystem to exotic species invasion. The invasive winter annual grass, Bromus tectorum (B. tectorum), is particularly competitive in disturbed semi-arid areas, has invaded tens of millions of hectares throughout the western US, and its range is projected to expand under predicted climate scenarios. Increasing soil moisture and resources in restoration projects may decrease soil moisture variability and promote establishment of a native plant community that is resilient to disturbance and resistant to invasion of B. tectorum. With their ability to absorb moisture when it is abundant and slowly release it over time, superabsorbent polymers (SAP) may increase overall soil moisture and decrease soil moisture variability during restoration. In this study, we aimed to investigate the interactive effects of precipitation timing, drought, B. tectorum, and SAP on soil resources and developing restoration plant communities. The study was established in 2014 at two climatically distinct sites : one site was located on the Eastern Slope (Larimer County) and one on the Western Slope (San Miguel County) of Colorado. Both sites fall under the mesic soil temperature regime and ustic-aridic soil moisture regime but vary in their susceptibility to invasion largely due to differences in seasonal precipitation patterns